6-hydrazino-2,3,5-trihalo-4-alkylthio pyridines and method of preparing same

Abstract

Novel compounds having the formula ##SPC1## Wherein R is an alkyl group of 1 to 5 carbons, X is Br or Cl and Y is Cl or is Br except when X is Cl, are prepared by the reaction of a hydrazine source material with a corresponding compound of the formula ##SPC2## The product compounds are fungicidal in their own right and are readily oxidized to highly active trihalo-4-alkylsulfonyl pyridine fungicides.

We claim: 
     
       1. A process for preparing a hydrazino-trihaloalkylthiopyridine of the formula ##SPC9## wherein R is an alkyl group of from 1 to 5 carbons; X is Cl or Br; and Y, which is the same in each occurrence, is Cl or Br, except that Y cannot be Br when X is Cl;   comprising reacting with hydrazine the corresponding tetrahalo-4-(alkylthio)pyridine of the formula ##SPC10## wherein R, X and Y are as above defined, thereby effecting replacement of one X in said tetrahalo-4-(alkylthio)pyridine with an --NH--NH 2  moiety.     
     
     
       2. The process of claim 1 additionally comprising reacting the resulting 6-hydrazino compound with an oxidant, thereby effecting replacement of the hydrazino moiety with a hydrogen. 
     
     
       3. The process of claim 2 in which said oxidant is employed under basic conditions. 
     
     
       4. The process of claim 2 in which the oxidant is hypochlorite or hypobromite ion. 
     
     
       5. The process of claim 2 additionally comprising reacting the resulting trihalo-4-(alkylthio)pyridine with an oxidant, thereby converting the alkylthio group to an alkylsulfinyl or alkylsulfonyl group. 
     
     
       6. The process of claim 5 wherein hypochlorite or hypobromite ion is employed as an oxidant at a pH above 7 to effect replacement of the hydrazino moiety and at a pH below 7 to effect oxidation of the alkylthio group.